Forms of the kind mentioned before are used for different applications. In an embodiment as a printing form, e.g. for letterpress printing, in particular for flexographic printing, the outer surface of the engraved elastomer layer forms the color transferring surface. For this reason, various requirements are made imposed for the elastomer layer and the surface thereof. For example, it must have a sufficient resistance against solvents present in the printing paint, a good dynamic performance, and color transfer performance, and a small swelling under the influence of printing paints, and after the printing process it must be easily and simply cleaned of the printing paint. The requirements are similar when the form is used for coating processes, e.g. as a transfer roller for flatbed printing, in particular offset printing. The term "coating" is to be understood in particular for the transfer of printing paints in the printing processes, in particular for flexographic printing, as well as the transfer of e.g. varnishes or glues onto web-shaped materials. Depending on the requirement, a transfer across the complete surface, and also a transfer only onto selected surface areas, is possible. When the form is used as an imprinting form, the elastomer layer in particular has to comprise a good dimension stability, and wear resistance even at the common temperatures of the material to be imprinted in imprinting processes, as well as a good separating performance in order to imprint web-shaped materials with a sufficient economy. Independent from the envisioned application of the form in any case, the elastomer layer must be well engraveable. The web-shaped materials to be printed with such a form, coated, or to be imprinted, as an example may be paper or textile webs, metal or plastic foils or compound materials comprising different materials.
Hitherto, elastomer layers fulfilling all mentioned requirements on the form could only be produced by vulcanization of elastomer compounds onto temperature stable carriers at a high temperature. The temperatures required for the vulcanization, in practical operation at least 140.degree. C., require the stock holding of appropriate devices for manufacturing the forms wherein particularly large printing forms having a length up to several meters and a circumference up to about 2 m require complicated heating devices. Therein correspondingly high energy costs are necessary for generating the required heat. Because the carrier onto which the elastomer layer is applied has to withstand the temperatures occurring during the vulcanization without damage, the selection of material for the carrier is considerably restricted namely to materials having a sufficient temperature stability. For practical reasons almost only metallic carriers may be used, whereas plastic carriers which would be preferred because of their lighter weight can hardly be used. Only premium glass fiber reinforced plastic materials are capable of coping with the high temperatures occurring during the vulcanization over the required time span. Hollow cylindrical light weight carriers may be made of these glass fiber reinforced plastic materials onto which the elastomer layer may be vulcanized, however, there is the disadvantage, that the possible variation in thickness of the carrier is very limited. Therefore, only relatively small repeat length areas may be covered in hollow cylindrical forms with a defined inner diameter for a certain firm mandrel roller outer diameter. In practical experience, it therefore happens, that in factories using the forms a very large number of different mandrel rollers have to be kept in stock. These mandrel rollers are expensive and require large warehouse space.